Fixed double quotes, added override annotation (#2592)

examples/strong/lib/animal.dart

@@ -12,14 +12,20 @@ class Animal {
 
 // #docregion HoneyBadger
 class HoneyBadger extends Animal {
+  @override
   void chase(Animal a) {/* ... */}
+
+  @override
   HoneyBadger get parent => ellipsis();
 }
 // #enddocregion HoneyBadger
 
 // #docregion chase-Object
 class HoneyBadger1 extends Animal {
+  @override
   void chase(Object a) {/* ... */}
+
+  @override
   Animal get parent => ellipsis();
 }
 // #enddocregion chase-Object

examples/strong/lib/strong_analysis.dart

@@ -22,7 +22,7 @@ void _miscDeclAnalyzedButNotTested() {
     void main() {
       var list = [];
       list.add(1);
-      list.add("2");
+      list.add('2');
       // ignore_for_file: stable, dev, argument_type_not_assignable
       printInts(list); //!analysis-issue
     }
@@ -77,15 +77,15 @@ void _miscDeclAnalyzedButNotTested() {
 
   {
     // #docregion local-var-type-inference-error
-    var x = 3; // x is inferred as an int
+    var x = 3; // x is inferred as an int.
     // ignore_for_file: stable, dev, invalid_assignment
     x = 4.0; //!analysis-issue
     // #enddocregion local-var-type-inference-error
   }
 
   {
     // #docregion local-var-type-inference-ok
-    num y = 3; // a num can be double or int
+    num y = 3; // A num can be double or int.
     y = 4.0;
     // #enddocregion local-var-type-inference-ok
   }
@@ -98,7 +98,7 @@ void _miscDeclAnalyzedButNotTested() {
     // Inferred as if you wrote <double>[3.0].
     var listOfDouble = [3.0];
 
-    // Inferred as Iterable<int>
+    // Inferred as Iterable<int>.
     var ints = listOfDouble.map((x) => x.toInt());
     // #enddocregion type-arg-inference
 

src/_guides/language/type-system.md

@@ -32,7 +32,7 @@ void printInts(List<int> a) => print(a);
 void main() {
   var list = [];
   list.add(1);
-  list.add("2");
+  list.add('2');
   printInts([!list!]);
 }
 {% endprettify %}
@@ -155,15 +155,21 @@ of Animal), but an unrelated type is not allowed.
 <?code-excerpt "strong/lib/animal.dart (HoneyBadger)" replace="/(\w+)(?= get)/[!$&!]/g"?>
 {% prettify dart tag=pre+code %}
 class HoneyBadger extends Animal {
+  @override
   void chase(Animal a) { ... }
+
+  @override
   [!HoneyBadger!] get parent => ...
 }
 {% endprettify %}
 
 {:.fails-sa}
 {% prettify dart tag=pre+code %}
 class HoneyBadger extends Animal {
+  @override
   void chase(Animal a) { ... }
+
+  @override
   [!Root!] get parent => ...
 }
 {% endprettify %}
@@ -198,7 +204,10 @@ It's OK to override the `chase()` method to take anything (Object).
 <?code-excerpt "strong/lib/animal.dart (chase-Object)" replace="/Object/[!$&!]/g"?>
 {% prettify dart tag=pre+code %}
 class HoneyBadger extends Animal {
+  @override
   void chase([!Object!] a) { ... }
+
+  @override
   Animal get parent => ...
 }
 {% endprettify %}
@@ -211,6 +220,7 @@ from Animal to Mouse, a subclass of Animal.
 class Mouse extends Animal {...}
 
 class Cat extends Animal {
+  @override
   void chase([!Mouse!] x) { ... }
 }
 {% endprettify %}
@@ -220,7 +230,7 @@ a cat and send it after an alligator:
 
 {% prettify dart tag=pre+code %}
 Animal a = Cat();
-a.chase([!Alligator!]()); // Not type safe or feline safe
+a.chase([!Alligator!]()); // Not type safe or feline safe.
 {% endprettify %}
 
 ### Don't use a dynamic list as a typed list
@@ -323,14 +333,14 @@ If so, you can add a type annotation.
 {:.fails-sa}
 <?code-excerpt "strong/lib/strong_analysis.dart (local-var-type-inference-error)"?>
 {% prettify dart tag=pre+code %}
-var x = 3; // x is inferred as an int
+var x = 3; // x is inferred as an int.
 x = 4.0;
 {% endprettify %}
 
 {:.passes-sa}
 <?code-excerpt "strong/lib/strong_analysis.dart (local-var-type-inference-ok)"?>
 {% prettify dart tag=pre+code %}
-num y = 3; // a num can be double or int
+num y = 3; // A num can be double or int.
 y = 4.0;
 {% endprettify %}
 
@@ -352,7 +362,7 @@ List<int> listOfInt = [];
 // Inferred as if you wrote <double>[3.0].
 var listOfDouble = [3.0];
 
-// Inferred as Iterable<int>
+// Inferred as Iterable<int>.
 var ints = listOfDouble.map((x) => x.toInt());
 {% endprettify %}